Industrial systems, particularly pneumatic systems require dry air or another dry gas. If regular ambient air was used there may be too much humidity in it causing corrosion and lack of desired performance. Typical air or other gas drying systems configured to provide dry gas for industrial uses often include adsorption chambers containing an adsorbent material. Over the course of the usage of the system, the adsorbent material may become saturated and cannot effectively or efficiently remove moisture from a gas.
As such, the adsorption chamber may need to be taken off-line and the adsorbent regenerated using a purge gas. Often, drying systems may use two or more different adsorption chambers in order for one adsorption chamber to be used drying the gas while the other adsorption chamber (or adsorption chambers) is(are) being regenerated. In such systems, valves may be used to take the adsorption chambers on and off-line as needed and to flow a purge gas through the off-line adsorption chamber to assist in regeneration of the adsorbent contained in the adsorption chamber.
In many instances the purge gas may be heated prior to entering the off-line adsorption chamber because heated purge gas may be more effective than non-heated purge gas in regenerating the adsorbent. In some instances, the systems may have a compressor which compresses the gas be dried. Compressors are well known to generate heat and it would be efficient if the heat from the compressor could be used to also heat the purge gas.
In some instances, a gas that is being compressed in the compressor has been used as a purge gas. However, in such systems care is taken to ensure that the compressor is a non-lubricated compressor in order to ensure contaminants such as lubricants do not find their way into the purge gas. Such contaminants can contaminate the adsorbent being regenerated causing the adsorbent to lose or reduce its effectiveness.
Accordingly, it is desirable to provide a method and apparatus that may use heat generated by the compressor without necessarily using a compressed gas by the compressor as a purge gas thereby avoiding some of the drawbacks of using compressed gas by the compressor as a purge gas.